v0.2.0: Prefer upstream tagged release version

• Prefer upstream tagged release version over master (HEAD),
  and download upstream release tarball if available,
  just like what uscan would do with our default debian/watch.
• Add -force-prerelease flag to revert to old behaviour
  of always choosing @master (git HEAD) over @latest tagged version.
• Generate debian/watch to track git HEAD if upstream has never
  tagged any release.
• Fix missing long description for non-GitHub import path
  when "go-source" meta tag actually resolves to GitHub.
• Add gitlab.com hoster as "gitlab", and blitiri.com.ar hoster as "blitiri".

v0.1.1

• Fix gbp import-orig call for -pristine-tar=true so that the pristine-tar branch is actually created if requested
• Stop adding Files-Excluded: Godeps/_workspace to debian/copyright if no such directory exists upstream
• Suppress Switched to a new branch 'debian/sid' message
• Use fmt.Printf() instead of log.Printf() for final instructions

v0.1.0

Start of semantic versioning, starting with v0.1.0

New flags -dep14, -pristine-tar and -wrap-and-sort have been added,
and the -type flag has been extended to support packages with both
library and program. Run dh-make-golang make -help for details.